the stunning announcement today from the vatican. why did pope benedict really say he is stepping down? and what does it mean for a billion catholics around the world? >>> in ruins. a tornado roaring up the street. electrical wires dangling. the massive cleanup tonight in one american town. >>> rescue. thousands of people stranded on a vacation cruise ship, cut off from the world. and the lifeboat on the way to try to help them tonight. >>> and, honor and valor. the emotional ceremony for a heroic soldier. the lesson he teaches about the american spirit. and an unlikely little star in a suit and tie. >>> good evening on this monday night. a centuries old tradition has been shattered by a surprise. pope benedict, chosen to be pope for life, today announced he will resign, citing his failing strength and health. and the toll of his seven years, nine months and 24 days as pope etched on his face. there he was, as we saw him on day one. and now, much thinner, frailer.